Virtualization Technology News and Information
VMware ESX guru Stephen Herrod offers tips for VI3 upgrades

Check out this interview article exchange between TechTarget columnist Andrew Kutz and VMware's Stephen Herrod.

In his day-to-day work, Dr. Stephen Herrod shapes the future of virtualization. Herrod, vice president of technology development at VMware, has spearheaded the development of several ESX Server releases. Prior to joining VMware, he helped lead the development of Transmeta Corp.'s code morphing technology. In this interview with columnist Andrew Kutz, Herrod discusses the challenges of upgrading to VMware Virtual Infrastructure 3 (VI3) how VMware categorizes virtualization, the future of grid computing and virtualization, ESX Server, VMFS and more. What are some hurdles current ESX administrators might face with during the upgrade to VI3?

Dr. Stephen Herrod: As with any major product upgrade, especially a mission-critical one, the most important element is to plan the upgrade.

There is a tremendous amount of new functionality in the products. We've put several things in place to help encourage and manage the transition. A few specific areas are worth calling out:

- - Virtual Center: Virtual Center 2.0 can manage mixed ESX Server version 2 and 3 environments. This allows you to take advantage of the new management functionality while transitioning your ESX servers.

- - Virtual Mmachines: Virtual machines (VMs) created on ESX Server 2.x can be brought into the new ESX Server 3.0 environment and will run fine without modification. In order to take advantage of the latest virtual hardware and features like four-way SMP, a virtual machine does need to be upgraded.

This is a one-way path upgrade, so customers will want to clone their virtual machines beforehand if they think they'll want to continue to use them on ESX Server 2.x hosts as well. For mass upgrading of a large number of the VMs (virtual machines) from Version 2 to Version 3 (that is, upgrading the virtual hardware, the on-disk file format, and the VMware Ttools), we've provided a batch VM upgrade script.

- - Virtual Machine File System (VMFS): VMware ESX Server 2.x uses version 2 of our VMFS file system. This file system should be upgraded to the newest version in order to take advantage of the VMware Infrastructure features.

We have several tools to aid in this move. For example, we support in-place upgrading of an existing VMFS 2 file system. This allows you to upgrade without any additional temporary storage needs. We also allow what we call "cold migration" to copy VMs from a previous VMFS 2 file system to a new VMFS 3 file system. Both processes do require some virtual machine downtime, so this needs to be planned. To avoid this downtime, we are actively working on a method of seamlessly moving live VMs between versions.


Microsoft believes that virtualization should be a component of the operating system, and XenSource believes that it should be a component of the infrastructure. Where does VMware believe that virtualization falls in the scheme of things?

Herrod: We believe that virtualization should be thought of along the lines of hardware. More specifically, we find that many of our customers treat it as a part of their compute and storage layer, thinking about it at hardware purchase time and expecting the same levels of reliability and performance. We also believe virtualization services should be independent of the operating system running within virtual machines.

Tight integration comes at the unfortunate cost of giving up a bias-free choice of operating system and thus the software stack (i.e., OS and application program). Customers who already have mixed software environments or who would like to have that option in the future will benefit from this lack of OS bias. And finally, tying the virtualization layer to an OS could push towards additional software dependencies.

Should you have to upgrade your virtualization layer if the guest operating system requires patching? We don't think so.


Read the rest of these great interview questions and answers by clicking here to read the entire article.


Published Sunday, August 13, 2006 10:22 AM by David Marshall
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